KR840000709B1 - Improvement in the process of polymerising vinyl chloride in seeded microsuspension - Google Patents

Abstract

Vinyl chloride polymer or copolymer is prepd. by means of polymerization in a seeded microsuspension contg. organic soluble initiator (A). A is an organic peroxide, such as lauroyl, decanoyl or caproyl peroxide, tertiary isobutyl diethyl peracetate, dihexyl percarbonate, or diacetyl peroxide, and is activated throughout the polymerization operation by an organic metal complex generated by the reaction between organic soluble metal salt and a complex compound of nitric acid and the metal complex.

Description

Method for producing vinyl chloride polymer in inoculated microsuspension

The present invention relates to an improved process for the preparation of vinyl chloride homopolymers and copolymers in inoculated microsuspensions.

According to French Patent Publication No. 1,485,547 and Additional Patent Publication No. 91,706, the polymerization of vinyl chloride in a microsuspension in the presence of an inoculum containing all the initiators required for polymerization is carried out in a single microsuspension. It is known that there is an advantage in that the consumption of the initiator is minimized, the reaction uniformity is increased, and the concentration of the polymer in the latex is increased, in addition to the low deadlock in the reaction zone.

Further, according to French Patent Publication No. 7,513,582 Publication No. (2,309,569) and Supplementary Patent Publication No. 7,608,025 (Public Publication No. 2,344,579), the particle size in the polymerization of vinyl chloride in a microsuspension It is possible to increase the polymer concentration in the resulting latex by using microsuspensions which are composed of two or more different inoculants and at least one of these inoculum contains all the initiators necessary for polymerization, It has been known that in addition to being able to reduce the viscosity and to improving the granularity of the particle size, it is possible to produce materials having properties which are particularly suitable for the production of plastisols.

Further, according to French Patent Publication No. 7,320,882 (Publication No. 2,234,321), an initiator is used throughout the polymerization operation using an organic soluble metal complex compound prepared in advance or produced by the reaction of a water-soluble metal salt with a complexing agent itself. It is known that activating can reduce the amount of initiator used, increase the rate of polymerization, and reduce the rate of deadlock in the reaction zone.

Using the above-described methods, vinyl chloride polymer can be produced on an industrial scale by inoculating microsuspension polymerization, but the following improvements, i.e., the yield method should be improved by reducing polymerization time and deadlock production. Or by reducing the amount of residues of water-soluble metal salts that may degrade the properties of the vinyl chloride polymer, such as thermal stability and UV stability. Attempt of is requested.

The present invention can solve the above problems. The method comprises a mixture of vinyl chloride or vinyl chloride with at least one copolymerizable monomer, consisting of one or more inoculum of different particle sizes prepared in advance, wherein at least one of the inoculum is subjected to polymerization in a microsuspension. And the polymerization is carried out in an inoculated microsuspension of a dispersion of vinyl polymer particles prepared by and containing all the organic solvents required for polymerization. At this time, the above-mentioned initiator is prepared in advance or is used in the entire polymerization operation using the organometallic complex produced by the reaction of the complexing agent and the organic soluble metal salt itself, characterized in that it is combined with nitric acid and the organic soluble metal complex. Is activated.

The content of vinyl chloride in the mixture of monomers is 50% by weight or more, and the copolymerizable monomers are those commonly used for copolymerization of vinyl chloride. Examples thereof include mono and vinyl, acetate, propionate and benzoate. Vinyl esters of polycarboxylic acids; Unsaturated mono and polycarboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, and aliphatic, alicyclic, aromatic esters, amides and nitriles thereof; Vinyl and vinylidene halides; Alkyl vinyl ethers; Olefins can be enumerated.

Examples of the vinyl polymer forming the inoculating material include polyvinyl chloride, copolymers of vinyl chloride and copolymerizable monomers described above, homopolymers of the monomers, and copolymers of the monomers. In a single operation, Polymers with different inoculum may be the same or different.

The inoculum containing the initiator (hereinafter referred to as the first inoculum) is composed of one or more monomers dispersed by a forced polymerization method in a commercially available polymerization method in a microsuspension, such as an aqueous medium containing an emulsifier as a stabilizer ( Homogenized), in the presence of an organic soluble initiator. This microsuspension forms an aqueous dispersion of particles of polymer having an average diameter of 0.05 to 1.5 μm, preferably 0.2 to 1 μm.

Organic solvents required for polymerization and contained in the polymer particles are generally used organic peroxides such as diacyl peroxides. Examples thereof include lauroyl, decanoyl, caproyl peroxides, and third isobutyldiethyl. Peracetate, diethylhexyl percarbonate, and diacetyl peroxide can be mentioned.

The choice of initiator is related to the rate of decomposition at the reaction temperature employed, and it is also possible to use an organic solvent in combination. In this case, it is preferable to use a thing with different reactivity.

The content of the organic solvent initiator contained in the inoculating polymer particles is 0.05 to 5% by weight based on the polymer. In other inoculants which may or may not contain an initiator, and the inoculum forms a dispersion of the vinyl polymer particles, the particles constituting the inoculum are different from one another and are different from the particle size of the first inoculum, which is usually 0.02 to 1.5 μm. It is preferable that it is 0.02-0.8 micrometer. Dispersions of these particles can be prepared in comparison with polymerization methods commonly used in microsuspensions or emulsions.

The amount of inoculum used in the polymerization according to the present invention is used so that the polymer content of the inoculum is contained in an amount of 1 to 50% by weight based on the sum of the vinyl chloride (with or without comonomer to polymerize) and the inoculum polymer. do. When two or more inoculants are used, the ratio of the first inoculum to other inoculum is 95/5 to 5/95 depending on the composition of the polymer to be prepared. In addition, the ratio between the inoculum and the total amount of the inoculum is selected within a range sufficient to perform polymerization or copolymerization without the addition of an initiator to supplement the amount of the organic soluble initiator contained in the polymer particles.

The water content required for the polymerization is 20 to 80% by weight of the total concentration of the polymer (S) and vinyl chloride (with or without other copolymerizable monomers) in the inoculum, based on the water content of the inoculum. %, Preferably 45 to 75% by weight.

The material to be inoculated in the polymerization medium and inoculated in the microsuspension method should be an amount capable of sufficiently dispersing the monomer without adding a new homogeneous medium.

It may be effective to improve the stability of the microsuspension by adding at least one anionic emulsifier together with at least one nonionic emulsifier before or during the polymerization operation. As the anionic emulsifier, fatty acid soaps such as alkyl sulfates, alkylsulfonates, alkylarylsulfonates, alkylphenoxybenzenesulfonates, vinylsulfonates, allylsulfonates, alkylsulfosuccinates and alkylphosphates of alkali metals are preferable. As the nonionic emulsifier, polycondensates of ethylene oxide or propylene oxide on various hydroxylated organic compounds are preferable.

The emulsifier content can be blended up to 3% by weight relative to the vinyl chloride or vinyl chloride-copolymerizable monomer mixture. This amount is the amount commonly used to give an effective effect on the reaction. However, in the case of the emulsifier which acts only as a stabilizer for the microsuspension and does not affect the granularity of the particles, even if used in a content outside the above range it does not depart from the scope of the present invention.

The reaction mixture is heated under autogenous pressure at the polymerization temperature and the heating temperature depends on the desired molecular weight and on the properties of the vinyl chloride polymer. This temperature is 10-85 degrees normally, and the range of 30-70 degrees is preferable.

In order to accelerate the polymerization rate, the organometallic complex compound prepared in advance or produced by the reaction of the water-soluble metal salt and the complexing agent itself is used to activate the initiator contained in the inoculum particles throughout the polymerization operation.

The metal salt is used in an amount such that the molar ratio of the metal salt / initiator is 0.05 to 8, and examples of the metal salt include iron, copper, cobalt, nickel, zinc, tin, titanium, vanadium, manganese, chromium and silver, sulfates, It is used in the form of water-soluble salts such as chloride, nitrate or acetate.

As the complexing agent, compounds which can act from the water-soluble form of the metal to the form soluble in vinyl chloride and which do not have any inhibitory effect on the polymerization and the activity of the initiator by the metal can be used. Examples of compounds that meet these requirements include monocarboxylic acids that are slightly soluble in water, such as perfluorobutyric acid, α-bromolauric acid, sulfosalicylic acid, naphthenic acid and octoic acid; Polycarboxylic acids such as succinic acid, tartaric acid, maleic acid and dihydroxymaleic acid and anhydrides thereof; Alkyl phosphoric acid such as di- (2-ethyl-) hexyl phosphoric acid; Lactones such as ascorbic acid, esters thereof and butyrolactone; The ketones which have a group which activates a carbonyl functional group in the (alpha), (beta) position like acetyl lactone, 1, 3- dihydroxy acetone, and benzoin, and carbazones, such as diphenylthiocarbazone, can be enumerated. The amount of the complexing agent depends on the polymerization temperature, the cooling capacity of the reactor, and the purity of the reagent, but the amount of the complexing agent is used in an amount such that the molar ratio of the complexing agent / metal salt is 0.5 to 4.5.

The metal salts may be introduced into the reaction medium before or during the polymerization operation, and may be introduced in the form of an aqueous solution, or in the case of the polymerization operation, in the form of a mixture dissolved in an emulsifier, or carried out for the introduction operation. As an aqueous solution with a complexing agent, it introduces into a complex compound type previously. The complexing agent is introduced either alone or in a solution dissolved in an emulsifier, or continuously with a metal salt.

To achieve better use of the activator nitric acid is added to the activator in an amount such that the molar ratio of nitric acid / metal salt is from 0.1 to 5, preferably from 0.2 to 3. Nitric acid is introduced in an aqueous solution of the reaction medium, alone or in combination with a metal, or with a complexing agent or complex.

The activity of the initiator by the complex can be inhibited at the end of the complexing agent or the introduction of the complex and / or upon conversion of the metal ions from the organic solubilization to its water soluble form, which is in addition to ethylenediamine tetraacetic acid in the reaction medium. The addition of a metal ion sequestrant selected from ethylenediamine tetraacetic acid, nitrilotriacetic acid, diethylenetriamine pentaacetic acid and N (2-hydroxyethyl) ethylenediamine triacetic acid is easily achieved. Metal ion sequestrants are used in ratios up to molar stoichiometry relative to metal salts.

The present invention also provides for the isolation of polymers and copolymers of vinyl chloride from the polymerization medium by known methods such as filtration, coagulation and drainage, scattering, centrifugation and atomization, followed by It relates to polymers and copolymers of vinyl.

The polymers and copolymers are formed from sheets, films, yarns, hollow products, cellular materials, calendering, extrusion, extrusion-blowing, injection and casting, molded articles, coating covers and coatings, rotary casting or dipping, and the like. Known methods can be used to produce molded articles for the use of plastisols.

Example 1

5000 g of water; 1170 g of inoculum, prepared by polymerization in a microsuspension, having a concentration of 34.2% by weight (400 g) of polyvinyl chloride containing 7.5 g of lauroyl peroxide and having an average particle diameter of 0.494 µm; 482 g of inoculant, which is prepared by polymerization in an emulsion and has a concentration of 41.5 wt% (200 g) of polyvinyl chloride, containing no initiator at all, having an average particle diameter of 0.112 µm; 354 g of an aqueous 19.8% by weight sodium dodecylbenzenesulfonate solution; 0.3 g of copper sulfate and 1000 g of vinyl chloride were introduced into a 25-liter autoclave, then heated at a temperature of 52 ° C. and autogenous pressure, and maintained at that temperature throughout the reaction.

When the temperature of the medium reaches 52 ° C., an aqueous solution containing 0.4 g / l ascorbic acid and 0.168 g / l nitric acid (d = 1.38) was introduced at a rate of 0.12 L / hour for 3 hours, and then 0.08 L / hr for 3 hours. It was introduced at a rate of time and at a rate of 0.04 L / hour until the end of the reaction.

When the pressure of the autoclave dropped by one bar, that is, after 10.5 hours, the introduction of the acid solution was stopped and degassing was performed on the unreacted monomer.

This gave 17000 g of a dispersion of polymer having a polymer concentration of 57% by weight, that is, an actual conversion rate of 91% relative to chlorine usage.

The amount of deadlock in the oclave was 122 g, which was 1.22 wt% based on the chlorine consumption. The resulting polymer consisted of two populations of particles having an average diameter of 1.12 μm and 0.2 μm, respectively.

The operation of Example 1 was repeated without using nitric acid as a comparative experiment. The polymerization time was performed for 10 hours 40 minutes. This gave 16500 g of a dispersion of polymer having a polymer concentration of 55.7% by weight, that is, a conversion rate of 86% by weight relative to chlorine usage. The deadlock in the autoclave was 175 g, which was 1.75 wt% based on the chlorine consumption.

The resulting polymer consisted of two populations of particles having an average diameter of 1.12 μm and 0.195 μm, respectively.

From the above results, it can be seen that the use of nitric acid results in a higher conversion and a smaller amount of deadlock.

Example 2

The same operation as in Example 1 was carried out except that the amount of copper sulfate used in Example 1 was used instead of 0.3g, and the results and the results of the comparative experiments are described below.

The effect of nitric acid on the results was observed.

Example 3

The same operation as in Example 1 was carried out except that copper sulfate was not introduced into the reaction vessel and the introduction ratio of the same aqueous solution of ascorbic acid and nitric acid was 0.25 g / L. In addition, the polymerization time was 10 hours.

This gave 17200 g of a dispersion of polymer having a polymer concentration of 57.8% by weight, that is, an actual conversion rate of 93.5% relative to chlorine usage. The amount of deadlock produced in the reaction vessel was 0.22% by weight based on the amount of chlorine used. The resulting polymer consisted of two populations of particles having an average diameter of 1.12 μm and 0.194 μm, respectively. The same experiment as above was carried out without using nitric acid to obtain the following results.

[Examples 4 to 9]

The operation of Example 3 and the corresponding comparative experiment operation were carried out except that the same amount of other metal salts in place of copper sulfate, and the same amount of other complexing agents in place of ascorbic acid, respectively, were used in Example 3. The operating conditions and results are listed in the following Table 1 together with the operating conditions and results of Example 3.

Example 10

6400 g of water; Prepared by polymerization in a microsuspension, 32.5% by weight (450 g) of polyvinyl chloride containing 7.70 g of lauroyl peroxide, 1386 g of inoculum having an average particle diameter of 0.521 μm, and 9000 g of vinyl chloride, for 25 l After introduction into the autoclave, heating was carried out at a temperature of 52 ° C. and autogenous pressure and maintained at this temperature throughout the reaction.

When the temperature of the medium reached 52 ° C., an aqueous solution containing 58 g / l of sodium dodecylbenzenesulfonate at a rate of 0.135 l / h for 8 hours and 0.25 g / l of copper sulfate, 0.4 g / l of ascorbic acid and nitric acid (d = 1.38) An aqueous solution containing 0.16 g / l was introduced at the same time at a rate of 0.09 l / hour.

When the pressure of the autoclave dropped to 2 bar, the introduction of the complex compound and the nitric acid solution was stopped, and degassed for the unreacted monomer. The same experiment was performed without using nitric acid as a comparative experiment. The results are described below.

Example 11

4000 g of water; It is prepared by polymerization in a microsuspension, and the concentration is 34.2% by weight (400 g) of polyvinyl chloride containing 7.5 g of lauroyl peroxide, 1170 g of inoculum having an average particle diameter of 0.494 μm, and 10000 g of vinyl chloride, for 25 l. After introduction into the autoclave, heating was carried out at a temperature of 52 ° C. and autogenous pressure and maintained at this temperature throughout the reaction. When the temperature of the medium reached 52 ° C., an aqueous solution containing 58 g / l of sodium dodecylbenzenesulfonate at a rate of 0.15 l / h for 8 hours and 0.25 g / l copper sulfate, 0.4 g / l ascorbic acid and 0.16 g / nitric acid An aqueous solution containing 1 L was introduced simultaneously for 10 hours 30 minutes at a rate of 0.10 L / hour. When the pressure of the autoclave dropped to 2 bar, the introduction of the complex compound and the nitric acid solution was stopped, and degassed with respect to the unreacted monomer.

As a comparative experiment, the same experiment (Comparative Experiment A) as above without using nitric acid and an experiment using the amount of active substance which did not use nitric acid but obtained substantially the same product as in Example 11 (Comparative Test B) were carried out. Conditions and results are described below.

From the above results, the addition of nitric acid to achieve the same results using the copper sulfate-ascorbic acid activator can reduce the amount of copper sulfate and ascorbic acid in half, thereby preventing the degradation of the polyvinyl chloride thermal stability produced. It can be seen.

Example 12

The same operation was carried out in Example 11, except that copper sulfate was dissolved at a rate of 0.22 g / L in the emulsifier solution and without using ascorbic acid and nitric acid.

The same experiment was repeated without using nitric acid as a comparative experiment and the results are described below.

Example 13

Except ascorbic acid was introduced into the emulsifier solution in Example 11 at the rate of 0.35 g / l, and the same operation was performed without using copper sulfate and nitric acid, and the following result was obtained.

Example 14

The same operation as in Example 3 was carried out except that 9550 g of vinyl chloride and 450 g of vinyl acetate were used in place of 10000 g of vinyl chloride in Example 3 to obtain the following results.

Example 15

265 kg of demineralized water; 68.5 kg of inoculum, prepared by polymerization in a microsuspension, having a concentration of 36.8 wt% (25.2 kg) polyvinyl chloride containing 0.3 kg of lauroyl peroxide and having an average particle diameter of 0.55 μm; 29.7 kg of inoculating material prepared by polymerization in an emulsifier and containing 40.5% by weight (12 kg) of polyvinyl chloride containing no initiator and having an average particle diameter of 0.13 µm; 17.3 kg of an aqueous 20.3 wt% sodium dodecylbenzenesulfonate solution and 500 kg of vinyl chloride were introduced into an 800-liter autoclave, and then the reaction mixture was heated at a temperature of 52 ° C. and autogenous pressure, and maintained at the temperature throughout the reaction. .

When the temperature of the medium reached 52 ° C, an aqueous solution containing 0.65 g / l copper sulfate, 1 g / l ascorbic acid and 0.83 g / l nitric acid was added for 4 hours at a rate of 2 l / hour until the reaction was completed, and then It was introduced at a rate of 1.4 l / hour at 3 hours and finally at 0.7 l / hour. When the internal pressure of the autoclave dropped by 3 bar, introduction of the complexing agent and the nitric acid solution was stopped, and degassing was performed on the unreacted monomer. As a comparative experiment, operation of Example 15 was repeated without using nitric acid, and the following result was obtained.

Claims (1)

A microsuspension prepared in advance, prepared by polymerization in one or more microsuspensions, and having at least one inoculum composed of a dispersion of vinyl polymer particles containing all the organic solvents required for polymerization. In which the reaction between the complexing agent and the water-soluble metal salt itself is carried out by polymerization of vinyl chloride or a mixture of vinyl chloride with at least one copolymerizable monomer and preliminarily prepared or combined with an organic soluble metal complex and nitric acid. A process for producing homopolymers and copolymers of vinyl chloride by polymerization in an inoculated microsuspension consisting of activating the initiator throughout the polymerization with the resulting organic soluble metal complex compound.